Robust Hybrid Control Using Recurrent Wavelet- Neural-Network Sliding-Mode Controller for Two- Axis Motion Control System

In this paper, a robust hybrid control system (RHCS) for achieving high precision motion tracking performance of a two-axis motion control system is proposed. The proposed AHCS incorporating a recurrent wavelet-neuralnetwork controller (RWNNC) and a sliding-mode controller (SMC) to construct a RRWNNSMC. The two-axis motion control system is an x-y table of a computer numerical control machine that is driven by two field-oriented controlled permanent-magnet synchronous motors (PMSMs) servo drives. The RWNNC is used as the main motion tracking controller to mimic a perfect computed torque control law and the SMC controller is designed with adaptive bound estimation algorithm to compensate for the approximation error between the RWNNC and the ideal controller. The on-line learning algorithms of the connective weights, translations and dilations of the RWNNC are derived using Lyapunov stability analysis. A computer simulation and an experimental are developed to validate the effectiveness of the proposed RHCS. All control algorithms are implemented in a TMS320C31 DSP-based control computer. The simulation and experimental results using star and four leaves contours are provided to show the effectiveness of the RHCS. The motion tracking performance is significantly improved using the proposed RHCS and robustness to parameter variations, external disturbances, cross-coupled interference and frictional torque can be obtained as well for the two-axis motion control system.

On the use of light sensors on CubeSat nanosatellites

The paper focuses on the usage of the TCS34725 light sensor in the motion control system of the SamSat-Science nanosatellite platform. The sensor is designed to determine the angle between the sensor normal and the direction to the light emitter center. We developed a technique for calibrating light sensors, carried out a series of experiments, verified the nominal characteristic of the light sensor, and found the dependency of mean squared deviation (MSD) of the sensor values on the angle of incidence of the light flux. Three layouts of light sensors on the lateral faces of the nanosatellite are considered: on a plane; on the faces of a quadrangular pyramid with an inclination angle of 45°; on the faces of a truncated quadrangular pyramid with an angle of inclination of 45°. We have chosen a circuit that provides measurements with minimum noise.

Automatic Motion Control System of Roundness Testing Machine

Roundness has an important role in terms of dividing the load equally, determining component life, determining adjustment conditions, determining rotation accuracy, and facilitating lubrication. To measure the roundness required a tool that can perform measurements with precision. With a roundness measuring instrument that has an automatic motion control system it will be able to produce more efficient data retrieval and higher accuracy than previous research. The control system in this tool is a system that regulates the automatic movement of the roundness gauge. Where the function of this automatic motion control system is to measure the test object using a chuck as a clamp, the indicator dial is directed by the X and Y axes to the data collection point on the test object which is connected to the driving motor. Axis Y moves in translation to direct the indicator dial on the "arm" to the pick-up point which moves automatically depending on the selected data collection mode, then the indicator dial starts taking measurement data until the measurement data retrieval is complete, then the motor moves from top to bottom, to perform reversible data retrieval. Stepper motor on the chuck will also move. There are 2 mode in this machine, it is mode 1, where the resulting data is in the form of a "ring" and for mode 2, the resulting data is “spiral”. It was found that the translational speed of the screw shaft in the vertical movement is 0.025 m/s and the horizontal linear speed is 0.026 m/s.

Modeling the Dependence of the Specific Impulse on the Temperature of the Heater of an Electrothermal Micro-Motor Based on the Results of Its Tests

The paper investigates the dependence of the specific impulse on the temperature of the heater of an electrothermal micro-motor in order to analyze the possibility of its use as a part of a motion control system for a small technological spacecraft. The possibility of using an electrothermal micro-motor for unloading the angular momentum of flywheel motors is considered.